Mercedes dominated Italian Grand Prix practice with Valtteri Bottas pipping teammate Lewis Hamilton for the fastest lap of the day.
Hamilton was quickest in a cloudy morning session with some rain, clocking a lap of one minute 21.537 seconds while Bottas was second, but the tables were turned in the dry afternoon running.
The Finn pulled out a 1:21.406 while Hamilton - who will oust Ferrari's Formula One leader Sebastian Vettel from the championship lead he has held all season if he wins the last European race of the year - was 0.056 slower.
Vettel, seven points clear of his British rival, was third in both sessions with the gap closing in the afternoon to just 0.140. He had been more than a second slower in the opening 90 minutes at Ferrari's home track.
"It's been a good day, a clean day," said Hamilton, who won in Belgium last weekend and is favourite to take a record 69th career pole position on Saturday.
"We got the running done, we got through our programme with no problems. The car seems nicely balanced here. We just have some work to do to eke out a little bit more performance.
"It looks quite close between us and the Ferraris, so I anticipate it's going to be similar to the last race in that sense."
Ferrari Kimi Raikkonen was fourth fastest in practice one and two.
The Ferrari fans will take heart that Mercedes also looked strong in Belgian Grand Prix practice at Spa last weekend. Ferrari closed the gap, with Vettel on Hamilton's tail throughout the race.
They will also be buoyed by the fact that no driver has won two races in a row this season.